Entry of the Ottoman Empire
The Ottoman Empire joined the Central Powers in October – November 1914, threatening Russia’s Caucasian territories and Britain’s communications with India and the East via the Suez canal. British action opened another front in the South with the Gallipoli (1915) and Mesopotamia campaigns, though initially, the Turks were successful in repelling enemy incursion. But in Mesopotamia, after the disastrous Siege of Kut (1915-16), the British reorganized and captured Baghdad in March 1917. Further to the west in Palestine, initial British failures were overcome with Jerusalem being captured in December 1917 and the Egyptian Expeditionary Force under Edmund Allenby going on to break the Ottoman forces at the Battle of Megiddo (September 1918).
Italian Participation
Italy, since 1882 notionally allied to the German and Austro-Hungarian Empires but with her own designs against Austrian territory in South Tyrol, Istria, and Dalmatia, and a secret 1902 understanding with France effectively nullifying her alliance commitments, joined the Allies in May 1915, declaring war against Germany fifteen months later. Italian action along the Austrian border pinned down large numbers of enemy troops, though the crushing German-Austrian victory of Caporetto (October 1917) temporarily eliminated Italy as a major threat.

The Fall of Serbia
After repulsing three Austrian invasions in August-December 1914, Serbia fell to a combined German, Austrian and Bulgarian invasion in October 1915. Serbian troops continued to hold out in Albania and Greece, where a Franco-British force had landed to offer assistance and to pressure the Greek government into war against the Central Powers.
The perception of war in 1914 was almost romantic, and its declaration was met with great enthusiasm by many people. The common view was that it would be a short war of maneuver with a few sharp actions (to “teach the enemy a lesson”) and would end with a victorious entry into the capital (the enemy capital, naturally) then home for a victory parade or two and back to “normal” life. There were some pessimists (like Lord Kitchener) who predicted the war would be a long haul, but “everyone knew” the War would be “Over by Christmas….”
The Trenching Begins
After their initial success on the Marne, Entente and German forces began a series of outflanking maneuvers to try to force the other to retreat, in the so-called Race to the Sea. France and Britain soon found themselves facing entrenched German positions from Lorraine to Belgium’s Flemish coast. The sides took set positions, the French and British seeking to take the offensive while the Germans sought to defend the territories they had occupied.
One consequence of this was that the German trenches were much better constructed than those of their enemy: the Anglo-French trenches were only intended to be ‘temporary’ before their forces broke through the German defenses. Neither side proved able to deliver a decisive blow for the next four years, though protracted German action at Verdun (1916) and Allied failure the following spring brought the French army to the brink of collapse as mass desertions undermined the front line.
Around 800,000 soldiers from Britain and the Empire were on the Western Front at any one time, 1,000 battalions each occupying a sector of the line from Belgium to the Arne and operating a month-long four-stage system unless an offensive was underway. The front contained over 6,000 miles of trenches. Each battalion held its sector for around a week before moving back to support lines and then the reserve lines before a week out-of-line, often in the Poperinge or Amiens areas.